P0430: Catalyst System Efficiency Below Threshold Bank 2
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - same situation as P0420 but for the other side of a V6/V8 engine. Fix before emissions testing.
Symptoms
- Check engine light, usually no drivability symptoms
- Sulfur smell, marginal fuel economy loss
- Failed emissions inspection
Likely causes, most common first
- Bank 2 catalytic converter efficiency below threshold
- Aging downstream oxygen sensor on bank 2
- Exhaust leak near bank 2 sensors
- Converter poisoned by misfires, coolant or oil ingestion
Read P0430 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0430 is the twin of P0420, pointing at bank 2 - the cylinder bank that does not contain cylinder 1, so it appears on V-shaped engines. The converter on that side is reported as inefficient by the rear oxygen sensor.
Diagnosis mirrors P0420: verify the rear sensor is alive and the exhaust is tight before condemning the converter. On V engines, compare both banks - if both catalyst codes appear together, look for a shared cause such as fuel trim problems or oil consumption rather than two coincidentally dead converters.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0430
“2019 Honda pilot with under 60k miles, no obvious symptoms but Codes P219B and P0430 coming up, multiple sites reporting common recall for fuel injector issue with these codes. Called dealer and reporting that VIN not covered even though codes/symptoms the same as other vehicles covered under recall. Estimated cost over $1000 to replace fuel injectors”2019 Honda Pilot · Jun 2026
“The malfunction indictator light came on due to diagnostic trouble code P0430 (front bank catalyst system efficiency below threshold [bank 2]) while driving. The vehicle has 64,240 miles and has had zero symptoms prior to the DTC appearing. This problem is noted in Service Bulletin 21-010 for Honda Pilots year 2017-2019, but my Vin was not included in the "Vin range". I am taking the vehicle in to the dealer for an inspection and diagnostic, but I believe the "Vin range" should be updated to include my vehicle.”2019 Honda Pilot · Apr 2026
“Currently showing DTC P219B (O2 Sensor Signal Biased/Stuck Lean - Bank 2 Sensor 1) along with P0430 . For prior years thru 2019, Honda has issued Service Bulletins 19-072 and 20-100 covering DTCs P030x, P219A, and P219B, which may involve PCM software updates, a Cylinder A/F Test, and potential injector replacement. However, they have not issued bulletins for 2020. My car only has 58,000 miles.”2020 Honda Pilot · Feb 2026
Show 7 more owner reports
“Fuel Injector issue - diagnosed at Mike's Automotive, a NAPA AutoCare Center by ASE certified technician. Codes were P0430 and P219B which indicates fuel injector issue. The Emmissions System Problem check engine light goes on and off at random times, reduced fuel economy by almost 5 mpg, hard shifting, stalling. All symptoms are in line with the recall for 2019 Honda Pilots however my VIN is not included in the recall, but I believe it should be. Honda wants me to bring my vehicle to a Honda Dealership to get diagnosed, diagnostic is my cost, though I've already paid for a diagnostic at a different repair shop.”2019 Honda Pilot · Nov 2025
“SUV check engine light for the emissions system came on 11/21/2025. The light does not stay on all the time, it goes on and off ever several days. During my state inspection, dealer diagnosed issue to a P0430 code and ran a cylinder AF test. It revealed that cylinders 2, 5 and 6 failed for rich conditions and stated the fuel injectors require replacement. Both the dealer and honda Corp. stated there is no coverage for this issue. I did find that this issue was found with previous years for my model and make, however my year is not covered for the warrenty extension. Honda service bulletin 20 - 100.”2020 Honda Pilot · Nov 2025
“My vehicle has P0420 and P0430 code errors, indicating a problem with the catalytic converters/emission system. There is a current recall on 2018 VW Atlas vehicles for this issue, but it does not include my vehicle. It appears this recall needs to be extended as the same issue is occurring on other 2018 VW Atlas vehicles.”2019 Volkswagen Atlas · Nov 2025
“Fuel Injectors failed after being replaced less than 50,000 miles ago. This is part of a larger Honda issue noted on Bulletin 21-010. It is causing my car to not accelerate appropriately which is dangerous when on the road. Honda inspected the vehicle and found code P219B. This after finding code P0430 in April 2025 causing me to have to replace catalytic coverters. The emissions system light turned on for each of these issues. Please include my VIN in the safety notice since it is clearly having the same issues as all the other 2019 Honda Pilots.”2019 Honda Pilot · Oct 2025
“Ford Customer Satisfaction Programs (CSPs) 23B11/24E04 for P0420/P0430 codes they did the update and now the check engine light is on all the time and they will not replace catalytic converter”2016 Lincoln MKX · Oct 2025
“Dashboard warning "Emissions System Problem". Trouble code - P0430 / Catalyst System Efficiency Below Threshold Bank 2. Brought it in to the dealer, and required the fuel injection to be replaced. There is recall for model year 2016-2019 Honda Pilot V6, but was told by the dealer this car was not part of the recall based on the VIN#. Fuel Pump was having problem, and replaced under recall on 09/28/2023 (54K miles).”2019 Honda Pilot · Oct 2025
“Intermittent P0420 and P0430 catalytic converter efficiency code. The Malfunction Indicator Lamp (MIL) will turn on for a while and then turn off for a while.”2018 Ford F-150 · Aug 2025
Cars that report P0430 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0430?
Yes - same situation as P0420 but for the other side of a V6/V8 engine. Fix before emissions testing.
How much does it cost to fix P0430?
Typical US repair costs range from $100 for the simplest fix (downstream o2 sensor (bank 2)) to $2,800 in the worst case. The right number depends on which cause your car has - see the causes list.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.